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Cameron DP, Sornkom J, Alsahafi S, Drygin D, Poortinga G, McArthur GA, Hein N, Hannan R, Panov KI. CX-5461 Preferentially Induces Top2α-Dependent DNA Breaks at Ribosomal DNA Loci. Biomedicines 2024; 12:1514. [PMID: 39062087 PMCID: PMC11275095 DOI: 10.3390/biomedicines12071514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 06/21/2024] [Accepted: 06/22/2024] [Indexed: 07/28/2024] Open
Abstract
While genotoxic chemotherapeutic agents are among the most effective tools to combat cancer, they are often associated with severe adverse effects caused by indiscriminate DNA damage in non-tumor tissue as well as increased risk of secondary carcinogenesis. This study builds on our previous work demonstrating that the RNA Polymerase I (Pol I) transcription inhibitor CX-5461 elicits a non-canonical DNA damage response and our discovery of a critical role for Topoisomerase 2α (Top2α) in the initiation of Pol I-dependent transcription. Here, we identify Top2α as a mediator of CX-5461 response in the murine Eµ-Myc B lymphoma model whereby sensitivity to CX-5461 is dependent on cellular Top2α expression/activity. Most strikingly, and in contrast to canonical Top2α poisons, we found that the Top2α-dependent DNA damage induced by CX-5461 is preferentially localized at the ribosomal DNA (rDNA) promoter region, thereby highlighting CX-5461 as a loci-specific DNA damaging agent. This mechanism underpins the efficacy of CX-5461 against certain types of cancer and can be used to develop effective non-genotoxic anticancer drugs.
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Affiliation(s)
- Donald P. Cameron
- ACRF Department of Cancer Biology and Therapeutics, Division of Genome Sciences and Cancer, The John Curtin School of Medical Research, The College of Health and Medicine, The Australian National University, Canberra, ACT 2601, Australia; (D.P.C.); (N.H.)
- Division of Cancer Research, Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia; (J.S.); (G.P.)
| | - Jirawas Sornkom
- Division of Cancer Research, Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia; (J.S.); (G.P.)
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC 3000, Australia;
| | - Sameerh Alsahafi
- School of Biological Sciences, Queen’s University Belfast, Belfast BT9 5DL, UK;
| | - Denis Drygin
- Pimera Therapeutics, 7875 Highland Village Place, Suite 412, San Diego, CA 92129, USA;
| | - Gretchen Poortinga
- Division of Cancer Research, Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia; (J.S.); (G.P.)
| | - Grant A. McArthur
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC 3000, Australia;
| | - Nadine Hein
- ACRF Department of Cancer Biology and Therapeutics, Division of Genome Sciences and Cancer, The John Curtin School of Medical Research, The College of Health and Medicine, The Australian National University, Canberra, ACT 2601, Australia; (D.P.C.); (N.H.)
| | - Ross Hannan
- ACRF Department of Cancer Biology and Therapeutics, Division of Genome Sciences and Cancer, The John Curtin School of Medical Research, The College of Health and Medicine, The Australian National University, Canberra, ACT 2601, Australia; (D.P.C.); (N.H.)
- Division of Cancer Research, Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia; (J.S.); (G.P.)
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3053, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Konstantin I. Panov
- School of Biological Sciences, Queen’s University Belfast, Belfast BT9 5DL, UK;
- Patrick G Johnston Centre for Cancer Research, Queen’s University Belfast, Belfast BT9 7AE, UK
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2
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Li P, Gai X, Li Q, Yang Q, Yu X. DNA-PK participates in pre-rRNA biogenesis independent of DNA double-strand break repair. Nucleic Acids Res 2024; 52:6360-6375. [PMID: 38682589 PMCID: PMC11194077 DOI: 10.1093/nar/gkae316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/06/2024] [Accepted: 04/16/2024] [Indexed: 05/01/2024] Open
Abstract
Although DNA-PK inhibitors (DNA-PK-i) have been applied in clinical trials for cancer treatment, the biomarkers and mechanism of action of DNA-PK-i in tumor cell suppression remain unclear. Here, we observed that a low dose of DNA-PK-i and PARP inhibitor (PARP-i) synthetically suppresses BRCA-deficient tumor cells without inducing DNA double-strand breaks (DSBs). Instead, we found that a fraction of DNA-PK localized inside of nucleoli, where we did not observe obvious DSBs. Moreover, the Ku proteins recognize pre-rRNA that facilitates DNA-PKcs autophosphorylation independent of DNA damage. Ribosomal proteins are also phosphorylated by DNA-PK, which regulates pre-rRNA biogenesis. In addition, DNA-PK-i acts together with PARP-i to suppress pre-rRNA biogenesis and tumor cell growth. Collectively, our studies reveal a DNA damage repair-independent role of DNA-PK-i in tumor suppression.
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Affiliation(s)
- Peng Li
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Xiaochen Gai
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Qilin Li
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Qianqian Yang
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Xiaochun Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
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3
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Ye H, Zhou X, Zhu B, Xiong T, Huang W, He F, Li H, Chen L, Tang L, Ren Z. Toxoplasma gondii suppresses proliferation and migration of breast cancer cells by regulating their transcriptome. Cancer Cell Int 2024; 24:144. [PMID: 38654350 DOI: 10.1186/s12935-024-03333-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 04/18/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Breast cancer is the most common cancer in women worldwide. Toxoplasma gondii (T. gondii) has shown anticancer activity in breast cancer mouse models, and exerted beneficial effect on the survival of breast cancer patients, but the mechanism was unclear. METHODS The effect of tachyzoites of T. gondii (RH and ME49 strains) on human breast cancer cells (MCF-7 and MDA-MB-231 cells) proliferation and migration was assessed using cell growth curve and wound healing assays. Dual RNA-seq was performed for T. gondii-infected and non-infected cells to determine the differentially expressed genes (DEGs). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Protein-Protein Interaction Networks analysis (PPI) were performed to explore the related signaling pathway and hub genes. Hub genes were validated using the Kaplan-Meier plotter database, and Pathogen Host Interaction (PHI-base) database. The results were verified by qRT-PCR. RESULTS The tachyzoites of T. gondii decreased the expression of Ki67 and increased the expression of E-cadherin, resulting in suppressing the proliferation and migration of infected human breast cancer cells. The inhibitory effect of T. gondii on breast cancer cells showed a significant dose-response relationship. Compared with the control group, 2321 genes were transcriptionally regulated in MCF-7 cells infected with T. gondii, while 169 genes were transcriptionally regulated in infected MDA-MB-231 cells. Among these genes, 698 genes in infected MCF-7 cells and 67 genes in infected MDA-MB-231 cells were validated by the publicly available database. GO and KEGG analyses suggested that several pathways were involved in anticancer function of T. gondii, such as ribosome, interleukin-17 signaling, coronavirus disease pathway, and breast cancer pathway. BRCA1, MYC and IL-6 were identified as the top three hub genes in infected-breast cancer cells based on the connectivity of PPI analysis. In addition, after interacting with breast cancer cells, the expression of ROP16 and ROP18 in T. gondii increased, while the expression of crt, TgIST, GRA15, GRA24 and MIC13 decreased. CONCLUSIONS T. gondii transcriptionally regulates several signaling pathways by altering the hub genes such as BRCA1, MYC and IL-6, which can inhibit the breast tumor growth and migration, hinting at a potential therapeutic strategy.
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Affiliation(s)
- Hengming Ye
- The School of Public Health, Sun Yat-Sen University, 74 Zhongshan 2nd Rd, Guangzhou, 510080, Guangzhou, China
- Public Health Service Center of Bao'an District, Shenzhen, 518102, China
| | - Xiaotao Zhou
- Public Health Service Center of Bao'an District, Shenzhen, 518102, China
| | - Bike Zhu
- Public Health Service Center of Bao'an District, Shenzhen, 518102, China
| | - Tiantian Xiong
- Public Health Service Center of Bao'an District, Shenzhen, 518102, China
| | - Weile Huang
- Public Health Service Center of Bao'an District, Shenzhen, 518102, China
| | - Feng He
- Public Health Service Center of Bao'an District, Shenzhen, 518102, China
| | - Hui Li
- Public Health Service Center of Bao'an District, Shenzhen, 518102, China
| | - Lihua Chen
- Shenzhen Hospital of Guangzhou University of Chinese Medicine (Futian), Shenzhen, 518034, China
| | - Luying Tang
- The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510630, China
| | - Zefang Ren
- The School of Public Health, Sun Yat-Sen University, 74 Zhongshan 2nd Rd, Guangzhou, 510080, Guangzhou, China.
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Wu D, Huang H, Chen T, Gai X, Li Q, Wang C, Yao J, Liu Y, Cai S, Yu X. The BRCA1/BARD1 complex recognizes pre-ribosomal RNA to facilitate homologous recombination. Cell Discov 2023; 9:99. [PMID: 37789001 PMCID: PMC10547766 DOI: 10.1038/s41421-023-00590-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 07/16/2023] [Indexed: 10/05/2023] Open
Abstract
The BRCA1/BARD1 complex plays a key role in the repair of DNA double-strand breaks (DSBs) in both somatic cells and germ cells. However, the underlying molecular mechanism by which this complex mediates DSB repair is not fully understood. Here, we examined the XY body of male germ cells, where DSBs are accumulated. We show that the recruitment of the BRCA1/BARD1 complex to the unsynapsed axis of the XY body is mediated by pre-ribosomal RNA (pre-rRNA). Similarly, the BRCA1/BARD1 complex associates with pre-rRNA in somatic cells, which not only forms nuclear foci in response to DSBs, but also targets the BRCA1/BARD1 complex to DSBs. The interactions between the BRCT domains of the BRCA1/BARD1 complex and pre-rRNA induce liquid-liquid phase separations, which may be the molecular basis of DSB-induced nuclear foci formation of the BRCA1/BARD1 complex. Moreover, cancer-associated mutations in the BRCT domains of BRCA1 and BARD1 abolish their interactions with pre-rRNA. Pre-rRNA also mediates BRCA1-dependent homologous recombination, and suppression of pre-rRNA biogenesis sensitizes cells to PARP inhibitor treatment. Collectively, this study reveals that pre-rRNA is a functional partner of the BRCA1/BARD1 complex in the DSB repair.
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Affiliation(s)
- Duo Wu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Huang Huang
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Tenglong Chen
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Xiaochen Gai
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Qilin Li
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Chunhui Wang
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Westlake Disease Modeling Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Jia Yao
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yu Liu
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shang Cai
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Westlake Disease Modeling Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Xiaochun Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
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5
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Ragupathi A, Singh M, Perez AM, Zhang D. Targeting the BRCA1/ 2 deficient cancer with PARP inhibitors: Clinical outcomes and mechanistic insights. Front Cell Dev Biol 2023; 11:1133472. [PMID: 37035242 PMCID: PMC10073599 DOI: 10.3389/fcell.2023.1133472] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 03/14/2023] [Indexed: 04/11/2023] Open
Abstract
BRCA1 and BRCA2 play a critical role in a variety of molecular processes related to DNA metabolism, including homologous recombination and mediating the replication stress response. Individuals with mutations in the BRCA1 and BRCA2 (BRCA1/2) genes have a significantly higher risk of developing various types of cancers, especially cancers of the breast, ovary, pancreas, and prostate. Currently, the Food and Drug Administration (FDA) has approved four PARP inhibitors (PARPi) to treat cancers with BRCA1/2 mutations. In this review, we will first summarize the clinical outcomes of the four FDA-approved PARPi in treating BRCA1/2 deficient cancers. We will then discuss evidence supporting the hypothesis that the cytotoxic effect of PARPi is likely due to inducing excessive replication stress at the difficult-to-replicate (DTR) genomic regions in BRCA1/2 mutated tumors. Finally, we will discuss the ongoing preclinical and clinical studies on how to combine the PARPi with immuno-oncology drugs to further improve clinical outcomes.
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6
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The BRCA1 BRCT promotes antisense RNA production and double-stranded RNA formation to suppress ribosomal R-loops. Proc Natl Acad Sci U S A 2022; 119:e2217542119. [PMID: 36490315 PMCID: PMC9897471 DOI: 10.1073/pnas.2217542119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
R-loops, or RNA:DNA hybrids, can induce DNA damage, which requires DNA repair factors including breast cancer type 1 susceptibility protein (BRCA1) to restore genomic integrity. To date, several pathogenic mutations have been found within the tandem BRCA1 carboxyl-terminal (BRCT) domains that mediate BRCA1 interactions with proteins and DNA in response to DNA damage. Here, we describe a nonrepair role of BRCA1 BRCT in suppressing ribosomal R-loops via two mechanisms. Through its RNA binding and annealing activities, BRCA1 BRCT facilitates the formation of double-stranded RNA between ribosomal RNA (rRNA) and antisense-rRNA (as-rRNA), hereby minimizing rRNA hybridization to ribosomal DNA to form R-loops. BRCA1 BRCT also promotes RNA polymerase I-dependent transcription of as-rRNA to enhance double-stranded rRNA (ds-rRNA) formation. In addition, BRCA1 BRCT-mediated as-rRNA production restricts rRNA maturation in unperturbed cells. Hence, impairing as-rRNA transcription and ds-rRNA formation due to BRCA1 BRCT deficiency deregulates rRNA processing and increases ribosomal R-loops and DNA breaks. Our results link ribosomal biogenesis dysfunction to BRCA1-associated genomic instability.
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Regulation of RNA Polymerase I Stability and Function. Cancers (Basel) 2022; 14:cancers14235776. [PMID: 36497261 PMCID: PMC9737084 DOI: 10.3390/cancers14235776] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
RNA polymerase I is a highly processive enzyme with fast initiation and elongation rates. The structure of Pol I, with its in-built RNA cleavage ability and incorporation of subunits homologous to transcription factors, enables it to quickly and efficiently synthesize the enormous amount of rRNA required for ribosome biogenesis. Each step of Pol I transcription is carefully controlled. However, cancers have highjacked these control points to switch the enzyme, and its transcription, on permanently. While this provides an exceptional benefit to cancer cells, it also creates a potential cancer therapeutic vulnerability. We review the current research on the regulation of Pol I transcription, and we discuss chemical biology efforts to develop new targeted agents against this process. Lastly, we highlight challenges that have arisen from the introduction of agents with promiscuous mechanisms of action and provide examples of agents with specificity and selectivity against Pol I.
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Gueiderikh A, Maczkowiak-Chartois F, Rosselli F. A new frontier in Fanconi anemia: From DNA repair to ribosome biogenesis. Blood Rev 2021; 52:100904. [PMID: 34750031 DOI: 10.1016/j.blre.2021.100904] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/14/2021] [Accepted: 10/26/2021] [Indexed: 12/27/2022]
Abstract
Described by Guido Fanconi almost 100 years ago, Fanconi anemia (FA) is a rare genetic disease characterized by developmental abnormalities, bone marrow failure (BMF) and cancer predisposition. The proteins encoded by FA-mutated genes (FANC proteins) and assembled in the so-called FANC/BRCA pathway have key functions in DNA repair and replication safeguarding, which loss leads to chromosome structural aberrancies. Therefore, since the 1980s, FA has been considered a genomic instability and chromosome fragility syndrome. However, recent findings have demonstrated new and unexpected roles of FANC proteins in nucleolar homeostasis and ribosome biogenesis, the alteration of which impacts cellular proteostasis. Here, we review the different cellular, biochemical and molecular anomalies associated with the loss of function of FANC proteins and discuss how these anomalies contribute to BMF by comparing FA to other major inherited BMF syndromes. Our aim is to determine the extent to which alterations in the DNA damage response in FA contribute to BMF compared to the consequences of the loss of function of the FANC/BRCA pathway on the other roles of the pathway.
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Affiliation(s)
- Anna Gueiderikh
- CNRS - UMR9019, Équipe labellisée "La Ligue contre le Cancer", 94805 Villejuif, France; Gustave Roussy Cancer Center, 94805 Villejuif, France; Université Paris-Saclay - Paris Sud, Orsay, France.
| | - Frédérique Maczkowiak-Chartois
- CNRS - UMR9019, Équipe labellisée "La Ligue contre le Cancer", 94805 Villejuif, France; Gustave Roussy Cancer Center, 94805 Villejuif, France; Université Paris-Saclay - Paris Sud, Orsay, France.
| | - Filippo Rosselli
- CNRS - UMR9019, Équipe labellisée "La Ligue contre le Cancer", 94805 Villejuif, France; Gustave Roussy Cancer Center, 94805 Villejuif, France; Université Paris-Saclay - Paris Sud, Orsay, France.
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9
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The Ribosomal Gene Loci-The Power behind the Throne. Genes (Basel) 2021; 12:genes12050763. [PMID: 34069807 PMCID: PMC8157237 DOI: 10.3390/genes12050763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Nucleoli form around actively transcribed ribosomal RNA (rRNA) genes (rDNA), and the morphology and location of nucleolus-associated genomic domains (NADs) are linked to the RNA Polymerase I (Pol I) transcription status. The number of rDNA repeats (and the proportion of actively transcribed rRNA genes) is variable between cell types, individuals and disease state. Substantial changes in nucleolar morphology and size accompanied by concomitant changes in the Pol I transcription rate have long been documented during normal cell cycle progression, development and malignant transformation. This demonstrates how dynamic the nucleolar structure can be. Here, we will discuss how the structure of the rDNA loci, the nucleolus and the rate of Pol I transcription are important for dynamic regulation of global gene expression and genome stability, e.g., through the modulation of long-range genomic interactions with the suppressive NAD environment. These observations support an emerging paradigm whereby the rDNA repeats and the nucleolus play a key regulatory role in cellular homeostasis during normal development as well as disease, independent of their role in determining ribosome capacity and cellular growth rates.
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10
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Alkailani M, Palidwor G, Poulin A, Mohan R, Pepin D, Vanderhyden B, Gibbings D. A genome-wide strategy to identify causes and consequences of retrotransposon expression finds activation by BRCA1 in ovarian cancer. NAR Cancer 2021; 3:zcaa040. [PMID: 33447827 PMCID: PMC7787265 DOI: 10.1093/narcan/zcaa040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 12/03/2022] Open
Abstract
It is challenging to identify the causes and consequences of retrotransposon expression in human disease due to the hundreds of active genomic copies and their poor conservation across species. We profiled genomic insertions of retrotransposons in ovarian cancer. In addition, in ovarian and breast cancer we analyzed RNAs exhibiting Bayesian correlation with retrotransposon RNA to identify causes and consequences of retrotransposon expression. This strategy finds divergent inflammatory responses associated with retrotransposon expression in ovarian and breast cancer and identifies new factors inducing expression of endogenous retrotransposons including anti-viral responses and the common tumor suppressor BRCA1. In cell lines, mouse ovarian epithelial cells and patient-derived tumor spheroids, BRCA1 promotes accumulation of retrotransposon RNA. BRCA1 promotes transcription of active families of retrotransposons and their insertion into the genome. Intriguingly, elevated retrotransposon expression predicts survival in ovarian cancer patients. Retrotransposons are part of a complex regulatory network in ovarian cancer including BRCA1 that contributes to patient survival. The described strategy can be used to identify the regulators and impacts of retrotransposons in various contexts of biology and disease in humans.
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Affiliation(s)
- Maisa Alkailani
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| | - Gareth Palidwor
- Ottawa Institute for Systems Biology, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
- Bioinformatics, Ottawa Hospital Research Institute, Ottawa, Ontario, K1H 8L6, Canada
| | - Ariane Poulin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| | - Raghav Mohan
- Pediatrics Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA 021145, USA
| | - David Pepin
- Pediatrics Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA 021145, USA
- Department of Surgery, Harvard Medical School, Boston, MA 021156, USA
| | - Barbara Vanderhyden
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, K1H 8L6, Canada
| | - Derrick Gibbings
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
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11
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Berthel E, Vincent A, Eberst L, Torres AG, Dacheux E, Rey C, Marcel V, Paraqindes H, Lachuer J, Catez F, de Pouplana LR, Treilleux I, Diaz JJ, Dalla Venezia N. Uncovering the Translational Regulatory Activity of the Tumor Suppressor BRCA1. Cells 2020; 9:cells9040941. [PMID: 32290274 PMCID: PMC7226996 DOI: 10.3390/cells9040941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/30/2020] [Accepted: 04/04/2020] [Indexed: 12/24/2022] Open
Abstract
BRCA1 inactivation is a hallmark of familial breast cancer, often associated with aggressive triple negative breast cancers. BRCA1 is a tumor suppressor with known functions in DNA repair, transcription regulation, cell cycle control, and apoptosis. In the present study, we demonstrate that BRCA1 is also a translational regulator. We previously showed that BRCA1 was implicated in translation regulation. Here, we asked whether translational control could be a novel function of BRCA1 that contributes to its tumor suppressive activity. A combination of RNA-binding protein immunoprecipitation, microarray analysis, and polysome profiling, was used to identify the mRNAs that were specifically deregulated under BRCA1 deficiency. Western blot analysis allowed us to confirm at the protein level the deregulated translation of a subset of mRNAs. A unique and dedicated cohort of patients with documented germ-line BRCA1 pathogenic variant statues was set up, and tissue microarrays with the biopsies of these patients were constructed and analyzed by immunohistochemistry for their content in each candidate protein. Here, we show that BRCA1 translationally regulates a subset of mRNAs with which it associates. These mRNAs code for proteins involved in major programs in cancer. Accordingly, the level of these key proteins is correlated with BRCA1 status in breast cancer cell lines and in patient breast tumors. ADAT2, one of these key proteins, is proposed as a predictive biomarker of efficacy of treatments recently recommended to patients with BRCA1 deficiency. This study proposes that translational control may represent a novel molecular mechanism with potential clinical impact through which BRCA1 is a tumor suppressor.
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Affiliation(s)
- Elise Berthel
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Anne Vincent
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Lauriane Eberst
- Centre Léon Bérard, Medical Oncology Department, Université de Lyon 1, F-69008 Lyon, France;
| | - Adrian Gabriel Torres
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (A.G.T.); (L.R.d.P.)
| | - Estelle Dacheux
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Catherine Rey
- ProfileXpert, UNIV-US7 INSERM-UMS 3453 CNRS, F-69000 Lyon, France; (C.R.); (J.L.)
| | - Virginie Marcel
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Hermes Paraqindes
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Joël Lachuer
- ProfileXpert, UNIV-US7 INSERM-UMS 3453 CNRS, F-69000 Lyon, France; (C.R.); (J.L.)
| | - Frédéric Catez
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Lluis Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (A.G.T.); (L.R.d.P.)
- Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain
| | - Isabelle Treilleux
- Department of Translational Research and Innovation, Centre Léon Bérard, F-69008 Lyon, France;
| | - Jean-Jacques Diaz
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Nicole Dalla Venezia
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
- Correspondence: ; Tel.: +33-426-556-745
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12
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Emerging Role of Eukaryote Ribosomes in Translational Control. Int J Mol Sci 2019; 20:ijms20051226. [PMID: 30862090 PMCID: PMC6429320 DOI: 10.3390/ijms20051226] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 12/15/2022] Open
Abstract
Translation is one of the final steps that regulate gene expression. The ribosome is the effector of translation through to its role in mRNA decoding and protein synthesis. Many mechanisms have been extensively described accounting for translational regulation. However it emerged only recently that ribosomes themselves could contribute to this regulation. Indeed, though it is well-known that the translational efficiency of the cell is linked to ribosome abundance, studies recently demonstrated that the composition of the ribosome could alter translation of specific mRNAs. Evidences suggest that according to the status, environment, development, or pathological conditions, cells produce different populations of ribosomes which differ in their ribosomal protein and/or RNA composition. Those observations gave rise to the concept of "specialized ribosomes", which proposes that a unique ribosome composition determines the translational activity of this ribosome. The current review will present how technological advances have participated in the emergence of this concept, and to which extent the literature sustains this concept today.
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13
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Abstract
Fanconi anemia (FA) is a disease of DNA repair characterized by bone marrow failure and a reduced ability to remove DNA interstrand cross-links. Here, we provide evidence that the FA protein FANCI also functions in ribosome biogenesis, the process of making ribosomes that initiates in the nucleolus. We show that FANCI localizes to the nucleolus and is functionally and physically tied to the transcription of pre-ribosomal RNA (pre-rRNA) and to large ribosomal subunit (LSU) pre-rRNA processing independent of FANCD2. While FANCI is known to be monoubiquitinated when activated for DNA repair, we find that it is predominantly in the deubiquitinated state in the nucleolus, requiring the nucleoplasmic deubiquitinase (DUB) USP1 and the nucleolar DUB USP36. Our model suggests a possible dual pathophysiology for FA that includes defects in DNA repair and in ribosome biogenesis.
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14
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He Z, Kannan N, Nemirovsky O, Chen H, Connell M, Taylor B, Jiang J, Pilarski LM, Fleisch MC, Niederacher D, Pujana MA, Eaves CJ, Maxwell CA. BRCA1 controls the cell division axis and governs ploidy and phenotype in human mammary cells. Oncotarget 2018; 8:32461-32475. [PMID: 28427147 PMCID: PMC5464802 DOI: 10.18632/oncotarget.15688] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 02/16/2017] [Indexed: 11/25/2022] Open
Abstract
BRCA1 deficiency may perturb the differentiation hierarchy present in the normal mammary gland and is associated with the genesis of breast cancers that are genomically unstable and typically display a basal-like transcriptome. Oriented cell division is a mechanism known to regulate cell fates and to restrict tumor formation. We now show that the cell division axis is altered following shRNA-mediated BRCA1 depletion in immortalized but non-tumorigenic, or freshly isolated normal human mammary cells with graded consequences in progeny cells that include aneuploidy, perturbation of cell polarity in spheroid cultures, and a selective loss of cells with luminal features. BRCA1 depletion stabilizes HMMR abundance and disrupts cortical asymmetry of NUMA-dynein complexes in dividing cells such that polarity cues provided by cell-matrix adhesions were not able to orient division. We also show that immortalized mammary cells carrying a mutant BRCA1 allele (BRCA1 185delAG/+) reproduce many of these effects but in this model, oriented divisions were maintained through cues provided by CDH1+ cell-cell junctions. These findings reveal a previously unknown effect of BRCA1 suppression on mechanisms that regulate the cell division axis in proliferating, non-transformed human mammary epithelial cells and consequent downstream effects on the mitotic integrity and phenotype control of their progeny.
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Affiliation(s)
- Zhengcheng He
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nagarajan Kannan
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.,Department of Laboratory Medicine and Pathology, Division of Experimental Pathology and Laboratory Medicine, Mayo Clinic, Rochester, MN, USA
| | - Oksana Nemirovsky
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Helen Chen
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marisa Connell
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian Taylor
- Department of Oncology, University of Alberta and Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Jihong Jiang
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Linda M Pilarski
- Department of Oncology, University of Alberta and Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Markus C Fleisch
- Department of Obstetrics and Gynaecology, Landesfrauenklinik, HELIOS University Medical Center, Wuppertal, Germany
| | - Dieter Niederacher
- Department of Gynaecology and Obstetrics, University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Germany
| | - Miguel Angel Pujana
- Breast Cancer and Systems Biology Unit, Program Against Cancer Therapeutic Resistance (ProCure), Catalan Institute of Oncology, IDIBELL, L'Hospitalet del Llobregat, Barcelona, Spain
| | - Connie J Eaves
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher A Maxwell
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada.,Michael Cuccione Childhood Cancer Research Program, BC Children's Hospital, Vancouver, British Columbia, Canada
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15
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Abstract
The nucleolus is a distinct compartment of the nucleus responsible for ribosome biogenesis. Mis-regulation of nucleolar functions and of the cellular translation machinery has been associated with disease, in particular with many types of cancer. Indeed, many tumor suppressors (p53, Rb, PTEN, PICT1, BRCA1) and proto-oncogenes (MYC, NPM) play a direct role in the nucleolus, and interact with the RNA polymerase I transcription machinery and the nucleolar stress response. We have identified Dicer and the RNA interference pathway as having an essential role in the nucleolus of quiescent Schizosaccharomyces pombe cells, distinct from pericentromeric silencing, by controlling RNA polymerase I release. We propose that this novel function is evolutionarily conserved and may contribute to the tumorigenic pre-disposition of DICER1 mutations in mammals.
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Affiliation(s)
- Benjamin Roche
- a Martienssen Lab, Cold Spring Harbor Laboratory , Cold Spring Harbor , NY , USA
| | - Benoît Arcangioli
- b Genome Dynamics Unit, UMR 3525 CNRS, Institut Pasteur , Paris , France
| | - Rob Martienssen
- a Martienssen Lab, Cold Spring Harbor Laboratory , Cold Spring Harbor , NY , USA.,c Howard Hughes Medical Institute, Cold Spring Harbor Laboratory , Cold Spring Harbor , NY , USA
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